SpringMVC 反射型跨站点脚本攻击
解决方案：
服务端校验，添加拦截器
配置web,xml
xssFilter
com.fh.filter.XssFilter
XssFilter
package com.fh.filter;
import com.fh.controller.base.BaseController;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang.StringUtils;
import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
@Slf4j
public class XssFilter extends BaseController implements Filter {
/**
* 不需要过滤的链接
*/
public List excludes = new ArrayList<>();
/**
* xss过滤开关
*/
public boolean enabled = false;
@Override
public void init(FilterConfig filterConfig) throws ServletException {
String tempExcludes = filterConfig.getInitParameter("excludes");
String tempEnabled = filterConfig.getInitParameter("enabled");
if (StringUtils.isNotEmpty(tempExcludes)) {
String[] url = tempExcludes.split(",");
for (int i = 0; url != null && i < url.length; i++) {
excludes.add(url[i]);
}
}
if (StringUtils.isNotEmpty(tempEnabled)) {
enabled = Boolean.valueOf(tempEnabled);
}
}
@Override
public void doFilter(ServletRequest request, ServletResponse response, FilterChain filterChain) throws IOException, ServletException {
HttpServletRequest req = (HttpServletRequest) request;
HttpServletResponse resp = (HttpServletResponse) response;
if (handleExcludeURL(req, resp)) {
filterChain.doFilter(request, response);
return;
}
filterChain.doFilter(new XssHttpServletRequestWrapper((HttpServletRequest) request), response);
}
@Override
public void destroy() {
// noop
}
private boolean handleExcludeURL(HttpServletRequest request, HttpServletResponse response) {
if (!enabled) {
return true;
}
if (excludes == null || excludes.isEmpty()) {
return false;
}
String url = request.getServletPath();
for (String pattern : excludes) {
Pattern p = Pattern.compile("^" + pattern);
Matcher m = p.matcher(url);
if (m.find()){
return true;
}
}
return false;
}
}
XssHttpServletRequestWrapper
package com.fh.filter;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.io.IOUtils;
import org.apache.commons.lang.StringUtils;
import org.springframework.http.HttpHeaders;
import org.springframework.http.MediaType;
import javax.servlet.ServletInputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.util.*;
@Slf4j
public class XssHttpServletRequestWrapper extends HttpServletRequestWrapper {
private HttpServletRequest orgRequest;
// html过滤
private final static HTMLFilter htmlFilter = new HTMLFilter();
public XssHttpServletRequestWrapper(HttpServletRequest request) {
super(request);
orgRequest = request;
}
@Override
public ServletInputStream getInputStream() throws IOException {
// 非json类型，直接返回
if (!isJsonRequest()) {
return super.getInputStream();
}
// 为空，直接返回
String json = IOUtils.toString(super.getInputStream(), "utf-8");
if (StringUtils.isBlank(json)) {
return super.getInputStream();
}
// xss过滤
json = xssEncode(json);
final ByteArrayInputStream bis = new ByteArrayInputStream(json.getBytes("utf-8"));
return new ServletInputStream() {
@Override
public int read() throws IOException {
return bis.read();
}
};
}
/**
* 覆盖getParameter方法，将参数名和参数值都做xss过滤。
*/
@Override
public String getParameter(String rawName) {
String value = super.getParameter(xssEncode(rawName));
if (StringUtils.isNotBlank(value)) {
value = xssEncode(value);
}
return value;
}
@Override
public String[] getParameterValues(String name) {
String[] parameters = super.getParameterValues(name);
if (parameters == null || parameters.length == 0) {
return null;
}
for (int i = 0; i < parameters.length; i++) {
parameters[i] = xssEncode(parameters[i]);
}
return parameters;
}
@Override
public Enumeration getParameterNames() {
Enumeration parameterNames = super.getParameterNames();
List list = new LinkedList<>();
if (parameterNames != null) {
while (parameterNames.hasMoreElements()) {
String rawName = parameterNames.nextElement();
String safetyName = xssEncode(rawName);
if (!Objects.equals(rawName, safetyName))
{
log.warn("请求路径: {},参数键: {}, xss过滤后: {}. 疑似xss攻击",
orgRequest.getRequestURI(), rawName, safetyName);
}
list.add(safetyName);
}
}
return Collections.enumeration(list);
}
@Override
public Map getParameterMap() {
Map map = new LinkedHashMap<>();
Map parameters = super.getParameterMap();
for (String key : parameters.keySet()) {
String[] values = parameters.get(key);
for (int i = 0; i < values.length; i++) {
values[i] = xssEncode(values[i]);
}
map.put(key, values);
}
return map;
}
/**
* 覆盖getHeader方法，将参数名和参数值都做xss过滤。
* 如果需要获得原始的值，则通过super.getHeaders(name)来获取
* getHeaderNames 也可能需要覆盖
*/
@Override
public String getHeader(String name) {
String value = super.getHeader(xssEncode(name));
if (StringUtils.isNotBlank(value)) {
value = xssEncode(value);
}
return value;
}
private String xssEncode(String input) {
return htmlFilter.filter(input);
}
/**
* 是否是Json请求
*/
public boolean isJsonRequest()
{
String header = super.getHeader(HttpHeaders.CONTENT_TYPE);
return StringUtils.startsWithIgnoreCase(header, MediaType.APPLICATION_JSON_VALUE);
}
}
HTMLFilter
package com.fh.filter;
import lombok.extern.slf4j.Slf4j;
import java.util.*;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
@Slf4j
public final class HTMLFilter {
/** regex flag union representing /si modifiers in php **/
private static final int REGEX_FLAGS_SI = Pattern.CASE_INSENSITIVE | Pattern.DOTALL;
private static final Pattern P_COMMENTS = Pattern.compile("", Pattern.DOTALL);
private static final Pattern P_COMMENT = Pattern.compile("^!--(.*)--$", REGEX_FLAGS_SI);
private static final Pattern P_TAGS = Pattern.compile("<(.*?)>", Pattern.DOTALL);
private static final Pattern P_END_TAG = Pattern.compile("^/([a-z0-9]+)", REGEX_FLAGS_SI);
private static final Pattern P_START_TAG = Pattern.compile("^([a-z0-9]+)(.*?)(/?)$", REGEX_FLAGS_SI);
private static final Pattern P_QUOTED_ATTRIBUTES = Pattern.compile("([a-z0-9]+)=([\"'])(.*?)\\2", REGEX_FLAGS_SI);
private static final Pattern P_UNQUOTED_ATTRIBUTES = Pattern.compile("([a-z0-9]+)(=)([^\"\\s']+)", REGEX_FLAGS_SI);
private static final Pattern P_PROTOCOL = Pattern.compile("^([^:]+):", REGEX_FLAGS_SI);
private static final Pattern P_ENTITY = Pattern.compile("&#(\\d+);?");
private static final Pattern P_ENTITY_UNICODE = Pattern.compile("&#x([0-9a-f]+);?");
private static final Pattern P_ENCODE = Pattern.compile("%([0-9a-f]{2});?");
private static final Pattern P_VALID_ENTITIES = Pattern.compile("&([^&;]*)(?=(;|&|$))");
private static final Pattern P_VALID_QUOTES = Pattern.compile("(>|^)([^<]+?)(<|$)", Pattern.DOTALL);
private static final Pattern P_END_ARROW = Pattern.compile("^>");
private static final Pattern P_BODY_TO_END = Pattern.compile("<([^>]*?)(?=<|$)");
private static final Pattern P_XML_CONTENT = Pattern.compile("(^|>)([^<]*?)(?=>)");
private static final Pattern P_STRAY_LEFT_ARROW = Pattern.compile("<([^>]*?)(?=<|$)");
private static final Pattern P_STRAY_RIGHT_ARROW = Pattern.compile("(^|>)([^<]*?)(?=>)");
private static final Pattern P_AMP = Pattern.compile("&");
private static final Pattern P_QUOTE = Pattern.compile("<");
private static final Pattern P_LEFT_ARROW = Pattern.compile("<");
private static final Pattern P_RIGHT_ARROW = Pattern.compile(">");
private static final Pattern P_BOTH_ARROWS = Pattern.compile("<>");
// @xxx could grow large... maybe use sesat's ReferenceMap
private static final ConcurrentMap P_REMOVE_PAIR_BLANKS = new ConcurrentHashMap();
private static final ConcurrentMap P_REMOVE_SELF_BLANKS = new ConcurrentHashMap();
/** set of allowed html elements, along with allowed attributes for each element **/
private final Map> vAllowed;
/** counts of open tags for each (allowable) html element **/
private final Map vTagCounts = new HashMap();
/** html elements which must always be self-closing (e.g. "![]()
") **/
private final String[] vSelfClosingTags;
/** html elements which must always have separate opening and closing tags (e.g. "") **/
private final String[] vNeedClosingTags;
/** set of disallowed html elements **/
private final String[] vDisallowed;
/** attributes which should be checked for valid protocols **/
private final String[] vProtocolAtts;
/** allowed protocols **/
private final String[] vAllowedProtocols;
/** tags which should be removed if they contain no content (e.g. "" or "") **/
private final String[] vRemoveBlanks;
/** entities allowed within html markup **/
private final String[] vAllowedEntities;
/** flag determining whether comments are allowed in input String. */
private final boolean stripComment;
private final boolean encodeQuotes;
private boolean vDebug = false;
/**
* flag determining whether to try to make tags when presented with "unbalanced"
* angle brackets (e.g. "" becomes " text "). If set to false,
* unbalanced angle brackets will be html escaped.
*/
private final boolean alwaysMakeTags;
/** Default constructor.
*
*/
public HTMLFilter() {
vAllowed = new HashMap<>();
final ArrayList a_atts = new ArrayList();
a_atts.add("href");
a_atts.add("target");
vAllowed.put("a", a_atts);
final ArrayList img_atts = new ArrayList();
img_atts.add("src");
img_atts.add("width");
img_atts.add("height");
img_atts.add("alt");
vAllowed.put("img", img_atts);
final ArrayList no_atts = new ArrayList();
vAllowed.put("b", no_atts);
vAllowed.put("strong", no_atts);
vAllowed.put("i", no_atts);
vAllowed.put("em", no_atts);
vSelfClosingTags = new String[]{"img"};
vNeedClosingTags = new String[]{"a", "b", "strong", "i", "em"};
vDisallowed = new String[]{};
vAllowedProtocols = new String[]{"http", "mailto", "https"}; // no ftp.
vProtocolAtts = new String[]{"src", "href"};
vRemoveBlanks = new String[]{"a", "b", "strong", "i", "em"};
vAllowedEntities = new String[]{"amp", "gt", "lt", "quot"};
stripComment = true;
encodeQuotes = true;
alwaysMakeTags = true;
}
/** Set debug flag to true. Otherwise use default settings. See the default constructor.
*
* @param debug turn debug on with a true argument
*/
public HTMLFilter(final boolean debug) {
this();
vDebug = debug;
}
/** Map-parameter configurable constructor.
*
* @param conf map containing configuration. keys match field names.
*/
@SuppressWarnings("unchecked")
public HTMLFilter(final Map conf) {
assert conf.containsKey("vAllowed") : "configuration requires vAllowed";
assert conf.containsKey("vSelfClosingTags") : "configuration requires vSelfClosingTags";
assert conf.containsKey("vNeedClosingTags") : "configuration requires vNeedClosingTags";
assert conf.containsKey("vDisallowed") : "configuration requires vDisallowed";
assert conf.containsKey("vAllowedProtocols") : "configuration requires vAllowedProtocols";
assert conf.containsKey("vProtocolAtts") : "configuration requires vProtocolAtts";
assert conf.containsKey("vRemoveBlanks") : "configuration requires vRemoveBlanks";
assert conf.containsKey("vAllowedEntities") : "configuration requires vAllowedEntities";
vAllowed = Collections.unmodifiableMap((HashMap>) conf.get("vAllowed"));
vSelfClosingTags = (String[]) conf.get("vSelfClosingTags");
vNeedClosingTags = (String[]) conf.get("vNeedClosingTags");
vDisallowed = (String[]) conf.get("vDisallowed");
vAllowedProtocols = (String[]) conf.get("vAllowedProtocols");
vProtocolAtts = (String[]) conf.get("vProtocolAtts");
vRemoveBlanks = (String[]) conf.get("vRemoveBlanks");
vAllowedEntities = (String[]) conf.get("vAllowedEntities");
stripComment = conf.containsKey("stripComment") ? (Boolean) conf.get("stripComment") : true;
encodeQuotes = conf.containsKey("encodeQuotes") ? (Boolean) conf.get("encodeQuotes") : true;
alwaysMakeTags = conf.containsKey("alwaysMakeTags") ? (Boolean) conf.get("alwaysMakeTags") : true;
}
private void reset() {
vTagCounts.clear();
}
private void debug(final String msg) {
if (vDebug) {
log.info(msg);
}
}
//---------------------------------------------------------------
// my versions of some PHP library functions
public static String chr(final int decimal) {
return String.valueOf((char) decimal);
}
public static String htmlSpecialChars(final String s) {
String result = s;
result = regexReplace(P_AMP, "&", result);
result = regexReplace(P_QUOTE, """, result);
result = regexReplace(P_LEFT_ARROW, "<", result);
result = regexReplace(P_RIGHT_ARROW, ">", result);
return result;
}
//---------------------------------------------------------------
/**
* given a user submitted input String, filter out any invalid or restricted
* html.
*
* @param input text (i.e. submitted by a user) than may contain html
* @return "clean" version of input, with only valid, whitelisted html elements allowed
*/
public String filter(final String input) {
reset();
String s = input;
debug("************************************************");
debug(" INPUT: " + input);
s = escapeComments(s);
debug(" escapeComments: " + s);
s = balanceHTML(s);
debug(" balanceHTML: " + s);
s = checkTags(s);
debug(" checkTags: " + s);
s = processRemoveBlanks(s);
debug("processRemoveBlanks: " + s);
s = validateEntities(s);
debug(" validateEntites: " + s);
debug("************************************************\n\n");
return s;
}
public boolean isAlwaysMakeTags(){
return alwaysMakeTags;
}
public boolean isStripComments(){
return stripComment;
}
private String escapeComments(final String s) {
final Matcher m = P_COMMENTS.matcher(s);
final StringBuffer buf = new StringBuffer();
if (m.find()) {
final String match = m.group(1); //(.*?)
m.appendReplacement(buf, Matcher.quoteReplacement(""));
}
m.appendTail(buf);
return buf.toString();
}
private String balanceHTML(String s) {
if (alwaysMakeTags) {
//
// try and form html
//
s = regexReplace(P_END_ARROW, "", s);
s = regexReplace(P_BODY_TO_END, "<$1>", s);
s = regexReplace(P_XML_CONTENT, "$1<$2", s);
} else {
//
// escape stray brackets
//
s = regexReplace(P_STRAY_LEFT_ARROW, "<$1", s);
s = regexReplace(P_STRAY_RIGHT_ARROW, "$1$2><", s);
//
// the last regexp causes '<>' entities to appear
// (we need to do a lookahead assertion so that the last bracket can
// be used in the next pass of the regexp)
//
s = regexReplace(P_BOTH_ARROWS, "", s);
}
return s;
}
private String checkTags(String s) {
Matcher m = P_TAGS.matcher(s);
final StringBuffer buf = new StringBuffer();
while (m.find()) {
String replaceStr = m.group(1);
replaceStr = processTag(replaceStr);
m.appendReplacement(buf, Matcher.quoteReplacement(replaceStr));
}
m.appendTail(buf);
s = buf.toString();
// these get tallied in processTag
// (remember to reset before subsequent calls to filter method)
for (String key : vTagCounts.keySet()) {
for (int ii = 0; ii < vTagCounts.get(key); ii++) {
s += "";
}
}
return s;
}
private String processRemoveBlanks(final String s) {
String result = s;
for (String tag : vRemoveBlanks) {
if(!P_REMOVE_PAIR_BLANKS.containsKey(tag)){
P_REMOVE_PAIR_BLANKS.putIfAbsent(tag, Pattern.compile("<" + tag + "(\\s[^>]*)?>"));
}
result = regexReplace(P_REMOVE_PAIR_BLANKS.get(tag), "", result);
if(!P_REMOVE_SELF_BLANKS.containsKey(tag)){
P_REMOVE_SELF_BLANKS.putIfAbsent(tag, Pattern.compile("<" + tag + "(\\s[^>]*)?/>"));
}
result = regexReplace(P_REMOVE_SELF_BLANKS.get(tag), "", result);
}
return result;
}
private static String regexReplace(final Pattern regex_pattern, final String replacement, final String s) {
Matcher m = regex_pattern.matcher(s);
return m.replaceAll(replacement);
}
private String processTag(final String s) {
// ending tags
Matcher m = P_END_TAG.matcher(s);
if (m.find()) {
final String name = m.group(1).toLowerCase();
if (allowed(name)) {
if (!inArray(name, vSelfClosingTags)) {
if (vTagCounts.containsKey(name)) {
vTagCounts.put(name, vTagCounts.get(name) - 1);
return "";
}
}
}
}
// starting tags
m = P_START_TAG.matcher(s);
if (m.find()) {
final String name = m.group(1).toLowerCase();
final String body = m.group(2);
String ending = m.group(3);
//debug( "in a starting tag, name='" + name + "'; body='" + body + "'; ending='" + ending + "'" );
if (allowed(name)) {
String params = "";
final Matcher m2 = P_QUOTED_ATTRIBUTES.matcher(body);
final Matcher m3 = P_UNQUOTED_ATTRIBUTES.matcher(body);
final List paramNames = new ArrayList();
final List paramValues = new ArrayList();
while (m2.find()) {
paramNames.add(m2.group(1)); //([a-z0-9]+)
paramValues.add(m2.group(3)); //(.*?)
}
while (m3.find()) {
paramNames.add(m3.group(1)); //([a-z0-9]+)
paramValues.add(m3.group(3)); //([^\"\\s']+)
}
String paramName, paramValue;
for (int ii = 0; ii < paramNames.size(); ii++) {
paramName = paramNames.get(ii).toLowerCase();
paramValue = paramValues.get(ii);
// debug( "paramName='" + paramName + "'" );
// debug( "paramValue='" + paramValue + "'" );
// debug( "allowed? " + vAllowed.get( name ).contains( paramName ) );
if (allowedAttribute(name, paramName)) {
if (inArray(paramName, vProtocolAtts)) {
paramValue = processParamProtocol(paramValue);
}
params += " " + paramName + "=\"" + paramValue + "\"";
}
}
if (inArray(name, vSelfClosingTags)) {
ending = " /";
}
if (inArray(name, vNeedClosingTags)) {
ending = "";
}
if (ending == null || ending.length() < 1) {
if (vTagCounts.containsKey(name)) {
vTagCounts.put(name, vTagCounts.get(name) + 1);
} else {
vTagCounts.put(name, 1);
}
} else {
ending = " /";
}
return "<" + name + params + ending + ">";
} else {
return "";
}
}
// comments
m = P_COMMENT.matcher(s);
if (!stripComment && m.find()) {
return "<" + m.group() + ">";
}
return "";
}
private String processParamProtocol(String s) {
s = decodeEntities(s);
final Matcher m = P_PROTOCOL.matcher(s);
if (m.find()) {
final String protocol = m.group(1);
if (!inArray(protocol, vAllowedProtocols)) {
// bad protocol, turn into local anchor link instead
s = "#" + s.substring(protocol.length() + 1, s.length());
if (s.startsWith("#//")) {
s = "#" + s.substring(3, s.length());
}
}
}
return s;
}
private String decodeEntities(String s) {
StringBuffer buf = new StringBuffer();
Matcher m = P_ENTITY.matcher(s);
while (m.find()) {
final String match = m.group(1);
final int decimal = Integer.decode(match).intValue();
m.appendReplacement(buf, Matcher.quoteReplacement(chr(decimal)));
}
m.appendTail(buf);
s = buf.toString();
buf = new StringBuffer();
m = P_ENTITY_UNICODE.matcher(s);
while (m.find()) {
final String match = m.group(1);
final int decimal = Integer.valueOf(match, 16).intValue();
m.appendReplacement(buf, Matcher.quoteReplacement(chr(decimal)));
}
m.appendTail(buf);
s = buf.toString();
buf = new StringBuffer();
m = P_ENCODE.matcher(s);
while (m.find()) {
final String match = m.group(1);
final int decimal = Integer.valueOf(match, 16).intValue();
m.appendReplacement(buf, Matcher.quoteReplacement(chr(decimal)));
}
m.appendTail(buf);
s = buf.toString();
s = validateEntities(s);
return s;
}
private String validateEntities(final String s) {
StringBuffer buf = new StringBuffer();
// validate entities throughout the string
Matcher m = P_VALID_ENTITIES.matcher(s);
while (m.find()) {
final String one = m.group(1); //([^&;]*)
final String two = m.group(2); //(?=(;|&|$))
m.appendReplacement(buf, Matcher.quoteReplacement(checkEntity(one, two)));
}
m.appendTail(buf);
return encodeQuotes(buf.toString());
}
private String encodeQuotes(final String s){
if(encodeQuotes){
StringBuffer buf = new StringBuffer();
Matcher m = P_VALID_QUOTES.matcher(s);
while (m.find()) {
final String one = m.group(1); //(>|^)
final String two = m.group(2); //([^<]+?)
final String three = m.group(3); //(<|$)
m.appendReplacement(buf, Matcher.quoteReplacement(one + regexReplace(P_QUOTE, """, two) + three));
}
m.appendTail(buf);
return buf.toString();
}else{
return s;
}
}
private String checkEntity(final String preamble, final String term) {
return ";".equals(term) && isValidEntity(preamble)
? '&' + preamble
: "&" + preamble;
}
private boolean isValidEntity(final String entity) {
return inArray(entity, vAllowedEntities);
}
private static boolean inArray(final String s, final String[] array) {
for (String item : array) {
if (item != null && item.equals(s)) {
return true;
}
}
return false;
}
private boolean allowed(final String name) {
return (vAllowed.isEmpty() || vAllowed.containsKey(name)) && !inArray(name, vDisallowed);
}
private boolean allowedAttribute(final String name, final String paramName) {
return allowed(name) && (vAllowed.isEmpty() || vAllowed.get(name).contains(paramName));
}
}